Re: [cc65] c64 question

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From: Ullrich von Bassewitz (uz_at_musoftware.de)
Date: 2001-03-10 14:57:19 

On Sat, Mar 10, 2001 at 02:41:18PM +0100, daniel pralle wrote:
> What about making it ATOMIC with SEI and CLI? There is a way to mask out
> the NMIs aswell on the ATARI and on the other system also, if not the
> possible interupts could limited to maskable interupts.

This would impose a pentalty, even if no C interrupt handler is used. Routines
modifying the stack pointer are called really often, and each of these
routines would need at least 4 additional cycles to execute. "At least"
because the correct way would be not to use cli/sei, but to save the old state
on the stack, switch off interrupts and restore the old state later.

I do prefer a solution that does not affect code that does not need this
solution. In other words: Most programs don't need the feature, so why should
they pay for it in terms of program size and execution speed?

Regards


	Uz


--
Ullrich von Bassewitz                                  uz_at_musoftware.de
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